Genetic Link Discovered Between Alcohol Use and Mental Health Disorders

By Grace Speller

Psychiatric disorders and alcoholism are extremely prevalent in the United States, and a current report reveals that 12.5 percent of Americans struggle with alcohol dependency, while nearly 19 percent have a diagnosed mental health disorder. In our country, suicide is the 10th leading cause of death, while excessive alcohol use is responsible for the deaths of over 88,000 Americans annually.

In recent years, many studies have shown that alcohol dependence can arise from numerous factors including genetic risks, environmental experiences, and interactions between these. Notable studies include the effect of cold climate on alcohol consumption, further analysis of the region of the brain stimulated by alcohol, and the “safe level”, if one exists, of alcohol on a weekly basis. Other research has led to a better understanding of the increased mental risks associated with underage drinking.

A new study published on Nov. 26th by Arpana Agrwapal, PhD, in Nature of Neuroscience, examined the interactions among specific genes known to be risk factors for alcohol dependence and mental health disorders. What set this study apart was its staggeringly large sample size: DNA collected from 40,000 to 100,000 individuals. This allowed for a comparison of gene interaction from a myriad of regions across the globe.

The results revealed that the majority of genetic factors associated with daily drinking differed from those associated with mental health disorders, meaning that drinking does not necessarily increase the risk of developing mental health disorders and vise versa. However, one specific gene, called ADH1B, stood out from the rest. AHD1B is a vital gene that helps in regulating the conversion of alcohol into acetaldehyde (which is known to intensify the undesirable effects of drinking). Agrwapal discovered that the ADH1B gene in subjects with a psychiatric illness works as a protective gene, preventing the overconsumption of alcohol. Researchers also found that some of the genetic risk factors related to alcohol dependence were linked to risk factors for schizophrenia, depression, ADHD, and abuse of marijuana and cigarettes.

Arpana Agrwapal and her team realized that there are numerous other genes that contribute to alcoholism and mental health disorders and plan to examine their interactions further. To do this, however, a much larger sample size is required. Agrwapal concluded that “the genetic susceptibility to alcohol dependence stems from the small, cumulative effects of a very large number of variants across the genome.”